1. Field of the Invention
The present invention relates to a dynamic intervertebral spacer implant to be placed into an intervertebral space left after the removal of damaged spinal disc material.
2. Description of the Related Art
Historically, methods of fusing two adjacent vertebrae of the spine intervertebrally have used implants of either natural bone or a synthetic material and having fixed dimensions. Although the devices are available in a range of sizes, the devices are not adjustable by the surgeon during the surgical procedure. Therefore, the surgeon must choose the size which most closely matches the desired height, length and width dimensions, and then make the device fit. This procedure may entail further resection of the bone, or addition of natural bone, attained from either an inventoried bone bank or a patient donor site. The procedure results in relatively long and more invasive surgeries which present a danger to the patient.
In cases where an all bone implant is used, the bone is shaped to complement the surgeon-prepared cavity into which it is to be implanted. When a synthetic implant is used, the bone is pulverized and packed into the interstices of the device, in order to promote bony ingrowth. Over time, fusion is accomplished by the growth of natural bone in the neighboring, subject vertebrae into the implant.
Improvements in design and materials have resulted in stronger implants. However, due to the usual shapes used for fusion implants, they are still subject to fracture.